To join two fibers or fiber optic connectors together, the quality of a fiber endface or fiber connector endface needs to meet certain standards to maximize coupling efficiency and ensure proper operation of the fiber or fiber connector. Generally, a fiber endface or fiber connector endface has a desirable geometry or topography as well as an acceptable surface quality. A desirable surface geometry and acceptable surface quality is usually achieved through an optical polishing process and tested by one or more special optical instruments to verify that the endface meets certain standards.
Different optical instruments have been employed to inspect the endface of a fiber or fiber connector. Examples include optical microscopes and interferometric techniques. Optical microscopes magnify undesirable surface defects. Interferometric techniques utilize principles of optical interference to generate a fringe pattern representing the surface profile being inspected. These optical instruments, however, tend to be large, expensive and require a great amount of time to inspect an endface surface. These limitations make it difficult for users of polishing mechanisms to efficiently test and retest fiber or fiber connector endfaces.
For example, to inspect a surface of an endface using optical instruments known in the art, the surface should be precisely aligned with respect to the optical instrument. In general, high precision alignment stages are used to manipulate, align and focus the test surface. Manipulation and alignment of a fiber optic or fiber connector endface can be difficult if the initial position of the testing surface deviates from its nominal position. Furthermore, the existence of a multi-axis adjustment mechanism used to align the test surface increases complexity, cost of the instrument and introduces an inherent need to frequently readjust the system. Most optical instruments used for inspecting fiber or fiber connector endfaces are fairly large, bench-top instruments designed for static laboratory use. The size and weight of these devices make them impractical for portable use.